Clemizole is a drug in clinical development for the treatment of hepatitis C virus (HCV) infection. Clemizole is a novel inhibitor of TRPC5 channels. Clemizole is an H1 antagonist. Clemizole, an antihistamine drug that was once widely used for treatment of allergic disease, was recently discovered to be a potent inhibitor (IC50, 24 nM) of the interaction between an HCV protein (NS4B) and HCV RNA. Although clemizole was widely used during the 1950s and 1960s, this was before contemporary regulatory requirements were established for new drug development, and there is very minimal information about its pharmacokinetics and metabolism.

Patent Blue V (E-131) is a synthetic dye used as a food coloring. In Europe, it is used in beverages, preserves of red fruits, desserts, confectionary. In medicine, Patent Blue V is used as a contrast agent for visualizing lymphatic vessels. Patent Blue V is also used in dentistry in a disclosing tablet to demonstrate the presence of plaque on teeth.